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On the relevance of acoustic measurements for creating realistic virtual acoustic environments

Siegfried Gündert, Stephan D. Ewert, Steven van de Par

Abstract

Geometrical approaches for room acoustics simulation have the advantage of requiring limited computational resources while still achieving a high perceptual plausibility. A common approach is using the image source model for direct and early reflections in connection with further simplified models such as a feedback delay network for the diffuse reverberant tail. When recreating real spaces as virtual acoustic environments using room acoustics simulation, the perceptual relevance of individual parameters in the simulation is unclear. Here we investigate the importance of underlying acoustical measurements and technical evaluation methods to obtain high-quality room acoustics simulations in agreement with dummy-head recordings of a real space. We focus on the role of source directivity. The effect of including measured, modelled, and omnidirectional source directivity in room acoustics simulations was assessed in comparison to the measured reference. Technical evaluation strategies to verify and improve the accuracy of various elements in the simulation processing chain from source, the room properties, to the receiver are presented. Perceptual results from an ABX listening experiment with random speech tokens are shown and compared with technical measures for a ranking of simulation approaches.

On the relevance of acoustic measurements for creating realistic virtual acoustic environments

Abstract

Geometrical approaches for room acoustics simulation have the advantage of requiring limited computational resources while still achieving a high perceptual plausibility. A common approach is using the image source model for direct and early reflections in connection with further simplified models such as a feedback delay network for the diffuse reverberant tail. When recreating real spaces as virtual acoustic environments using room acoustics simulation, the perceptual relevance of individual parameters in the simulation is unclear. Here we investigate the importance of underlying acoustical measurements and technical evaluation methods to obtain high-quality room acoustics simulations in agreement with dummy-head recordings of a real space. We focus on the role of source directivity. The effect of including measured, modelled, and omnidirectional source directivity in room acoustics simulations was assessed in comparison to the measured reference. Technical evaluation strategies to verify and improve the accuracy of various elements in the simulation processing chain from source, the room properties, to the receiver are presented. Perceptual results from an ABX listening experiment with random speech tokens are shown and compared with technical measures for a ranking of simulation approaches.
Paper Structure (16 sections, 4 equations, 3 figures, 2 tables)

This paper contains 16 sections, 4 equations, 3 figures, 2 tables.

Table of Contents

  1. Introduction
  2. Room acoustic measurements of a real room
  3. Measurement setup
  4. Room Impulse Response measurement method
  5. Boundary properties
  6. Simulation of Binaural Room Impulse Responses recreating the real room
  7. Simulation methods
  8. Direct sound compensation method
  9. Technical evaluation of measured Binaural Room Impulse Responses
  10. ABX Listening Test
  11. Results
  12. Room acoustic measurements
  13. Technical evaluation of BRIRs
  14. ABX Listening Test
  15. Discussion
  16. ...and 1 more sections

Figures (3)

  • Figure 1: Left: Geometrical layout of the sources and receiver. Sources S1 to S4, at a height of 1.3 m, oriented towards the receiver. Source S5 and S6, at a height of 1.5 m, oriented away from the receiver. Right: Layout in the room.
  • Figure 2: Objective room acoustic parameters of BRIRs for source S1 over octave center frequency. The measured reference is shown in black and the colored bars represent the different methods in the same order as the legend. JND values are added to allow for a comparison with perceptual limits.
  • Figure 3: Results of the ABX listening test. Sensitivity $d'$ is shown on the left for differencing decision rule sorted over condition and subject. The right ordinate shows unbiased percentage correct values.